Two mass shootings in less than 24 hours – one in El Paso, Texas and another in Dayton, Ohio – have many asking: how do you protect yourself in an active shooter situation, particularly one in a public setting?

Such attacks could come in a variety of forms, according to the Department of Homeland Security, including the use of firearms, vehicles, improvised explosive devices or other methods to target crowds.

The main advice from Homeland Security is to remain vigilant and “if you see something, say something,” meaning to report suspicious behavior, items or activities to authorities.